Colour sequential displays are often used when size, weight, cost and alignment precision outweigh brightness, bit depth and speed (frame rate) as performance criteria. These displays use a rapid sequence of monochrome images and rely on the time-integration properties of the human eye to yield a full-colour image for each frame of the video image. Typically the image sequence consists of one or more repetitions of three primary colours (red, green, blue) but may include additional colours for expanded gamut or increased brightness. Unfortunately, if the viewer's eye is moving across the display (for example, when tracking an object that is moving in the image) the monochrome images can become spatially separated on their retina, resulting in motion-blur and colour fringe artifacts. Colour fringe artifacts are false (unintended) colours that can appear at the interfaces between objects of significantly different colours in the image, in particular, at the interface between less saturated colours and dark areas.